Description:Haze from Indonesian forest fires continued to plague Singapore on Friday (June 21) worrying workers and residents in the city state. Singapore, which usually enjoys clear skies, saw its air quality deteriorate sharply on Monday (June 17). Its pollution standards index (PSI) soared to a record of 401 at 12pm (0400 GMT) on Friday, easily exceeding the record of 226 hit in 1997. A PSI reading above 300 is deemed "hazardous" by the National Environmental Agency.(0:40)